So somewhere on the forum someone mentioned that you should squeeze the bottle then cap is to allow more CO2 to fill the bottles. I think this is a good idea. Another tip is that if you are using reusable plastic bottles with screw on caps, to ensure there is no CO2 leak keep the bottles upside down during fermentation. Seems to work better for me. First batch took 4 days to ferment, second batch took 1.

I'm no brewing pro, but I might have a few things to add to these tips as just "food for thought". The squeezing the bottle trick, my wife and kids do that when we buy pop and they kind of introduced me to this idea. Now when it comes to brewing root beer, it may not be a bad idea but I would think that it might be possible that once it ferments for so long the bottle may not tighten up or could take much longer to get to that point. I also was told that the amount of carbonation is based on how much yeast is put into the batch. I don't know if this is true or not, but if it is then I would also wonder again, will the bottle tighten up if this squeeze method is used? If it doesn't doesn't tighten up, will you know when its done fermenting?s

If you are wanting to check for CO2 leakage you could submerge the bottles in water and see if you get any bubbles. You could even, ever so lightly, squeeze the bottle just to see if you can push a bubble or twos worth of bubbles from the bottle. If you get no bubbles than its all good. Also, keep in mind that if your bottles are upside down, the sediment in the bottles will settle down to your cap rather than the bottom of the bottle. This may cause you t get a mouth full of that stuff when you open it to partake of the first sip. If you were really wanting to leave the bottles upside down, a few hours before enjoying your brew, I would shake them up just a little to break the sediment up then tip them upright so that the sediment settles to the bottom of the bottles.

Like I said, I'm not brewing pro, just kind of thinking this through and hopping it might help you in finding something that will work for you. Good luck and let us know how it all goes.

Actually, the amount of carbonation has nothing to do with how much yeast you use - the yeast will reproduce to make more yeast as needed. All adding more yeast does is speed up the fermentation process. What creates more carbonation (and also more alcohol) is more sugar. Once the yeast runs out of sugar, it goes dormant (and some dies off) and no more carbonation is produced. The choice of which type of yeast you use will determine what the ratio of carbonation to alcohol is, and how fast you get there. Different yeasts have different tolerances to CO2 and alcohol -- remember, those two are basically the yeast's excrement, and wading in its own excrement will kill off yeast. Wine/champagne yeasts have a higher tolerance to alcohol content (generally 14-16%) while beer/ale yeast are lower. Heck, Sam Adams bred a special yeast (took them more than a decade) for their Utopias beer that tops out at 27% - the highest alcohol content of any fermented beverage, ever (you can only get higher proof by distilling).

And, to give one last little UMPH (burst of carbonation) to the yeast, leave a little bit of corn sugar at the bottle as you bottle up the brew.

Now, make note, I said corn sugar, NOT corn syrup. HFCS, High Fructose Corn Syrup, which is pretty much the same thing as the corn syrup you can buy in the store, is fructose. Corn Sugar is made from the stalk of the corn plant, and is actually dextrose, a completely different sugar. At home brew stores, dextrose/corn sugar is also know as priming sugar. Dextrose turbo-charges the yeast - makes it go into a fermentation frenzy, so use sparingly and carefully. Over-using dextrose will likely result in burst plastic bottles (and even possibly broken glass bottles if they are thin-walled like the ones you buy sodas and beers in).